$ show ninxsoft/Mist
Mist is a native macOS SwiftUI application for Mac admins and IT teams that discovers, downloads, validates, and packages macOS Firmware (IPSW restore images for Apple Silicon) and macOS Installers. It pulls firmware metadata from the third-party IPSW Downloads API and installer metadata by parsing Apple Software Update catalogs (sucatalog) plus their .dist distribution files. The app handles very large downloads with retry and resume logic, validates integrity via SHA-1 for firmware and Apple's binary chunklist (integrityDataV1) format for installer packages, then assembles distributable artifacts: .app bundles, .dmg disk images, .iso bootable images for virtualization, and signed or unsigned .pkg packages. It can also write bootable installers to external Mac OS Extended volumes. Architecturally it is a two-process macOS application: a SwiftUI client plus a privileged helper daemon installed via Blessed and communicated with over SecureXPC. Privileged operations (removing protected paths, repairing file ownership/permissions, running installer and createinstallmedia) execute in the helper; non-privileged tools (hdiutil, pkgbuild, codesign) run in-process through a thin Process wrapper. The whole download/export workflow is modeled as ordered MistTask sections (download, setup, build, cleanup) executed serially with live progress UI, a unified log, and notification-center alerts. Exports support CSV, JSON, plist, and YAML. Engineering quality is strong: CI-enforced SwiftLint (with ~40 opt-in rules), SwiftFormat, and DrString doc-comment validation keep the code remarkably consistent; the Model/Helper/Extension structure is clean; and Swift 6 concurrency is used throughout. The most genuinely reusable pieces are self-contained: Apple chunklist binary parsing, IOKit hardware introspection, a process-execution abstraction, and chunked SHA-256 file verification. Weaknesses are the near-useless unit test (XCTAssertTrue(true)), duplicated dist-file regex parsing and keychain-identity query logic across views, and a URLSession download bridge that uses a blocking DispatchSemaphore instead of async continuations. A companion CLI (mist-cli) exists as a separate project.
The LLM identified 5 files worth highlighting for reuse:
Parses Apple's binary .chunklist format used by Software Update catalogs to validate downloaded packages. It reads a fixed header (magic 0x4C4B4E43, version, chunk method), validates every header field, then decodes an array of 36-byte chunk records (UInt32 size + SHA-256 hash) and verifies chunk count and signature offset arithmetic. Self-contained (Foundation only) and demonstrates careful little-endian binary decoding with explicit offset math; directly reusable in any tool that must consume Apple's chunked integrity metadata.
Discovers hardware identity from the IOPlatformExpertDevice IOKit registry: CPU architecture (arm64/x86_64), Intel board-id, Apple Silicon/T2 device id (via the 'compatible' property), and model identifier. Handles CFTypeRef bridging, memory management (takeRetainedValue, IOObjectRelease), and null-byte stripping defensively. Self-contained and directly reusable for any macOS system tool needing hardware compatibility gating.
A minimal, reusable wrapper around Foundation's Process that launches /usr/bin/env with arguments, captures stdout and stderr into strings, returns termination status via a Codable response struct, and supports injecting environment variables and a working directory. Also exposes terminate() for cancellation. Compiled into both the app and the privileged helper, it cleanly isolates the only Process usage in the codebase. Easy to lift into any Swift tool that needs command execution with captured output.
Performs integrity verification for downloaded firmware (whole-file SHA-1) and installer packages (Apple chunklist-driven SHA-256). The chunked path is non-trivial: it streams the file via FileHandle seek/read, hashes each chunk per the parsed chunklist, checks Task.checkCancellation() between chunks, and reports byte-level mismatches with expected vs actual hashes. The incremental-hash approach avoids loading multi-GB download payloads into memory and is directly portable to other download-verification tooling.
A URLSessionDownloadTask-based downloader with retry, exponential resume-data recovery, and user-cancellation detection. On URLError it extracts downloadTaskResumeData to resume interrupted transfers, sleeps per configured delay, and enforces a maximum retry count. It exposes a cancelTask() hook wired to the app's Escape-key cancellation. Only imports Foundation. The DispatchSemaphore callback bridge is dated (a continuation would be cleaner), but the resume/retry semantics are a proven pattern for large-file downloads.